这篇文章主要介绍了php强制用户转向www域名的方法,可实现模拟301重定向的功能,并且针对无法head重定向的情况输出链接,需要的朋友可以参考下

本文实例讲述了php强制用户转向www域名的方法。分享给大家供大家参考。具体分析如下：

有时候网站的www域名和非www域名都能访问网站，但是这样不利于搜索引擎的收录，会分散网页的权重，所以希望用户访问非www的域名时通过301永久重定向到www域名，例如用户访问phpfensi.com会直接转向www.phpfensi.com，本php代码考虑了无法通过head重定向的情况，会在页面上输出链接，让用户点击。

1. // Install info.:
2. // Copy and paste these lines into your default index.php or
3. // the file that get's called if a visitor comes on your
4. // website...
5. // read the host from the server environment
6. $host = $_SERVER["HTTP_HOST"];
7. // fix host name - we never now... ;-)
8. $host = strtolower($host);
9. $host = trim($host);
10. // This is important:
11. // Webbrowsers like Firefox are doing their request without
12. // the port number like "www.phpfensi.com" but some other
13. // applications send host names like "www.phpfensi.com:80"
14. $host = str_replace(':80', '', $host);
15. $host = trim($host);
16. // if the host is not starting with www. redirect the
17. // user to the same URL but with www :-)
18. if ($host != 'www.phpfensi.com'){
19. // You an also change the "!=" to "==", if you want to force
20. // the user to use the domain name without the www.
21. // send status header, so that search engines or other services
22. // detect that this is a permanent redirect and not a temporary
23. header('HTTP/1.1 301 Moved Permanently');
24. // read the URL the user requested:
25. $url = isset($_SERVER["REQUEST_URI"]) ? $_SERVER["REQUEST_URI"] : '';
26. // redirect the user to the new destination:
27. header('Location: https://www.phpfensi.com' . $url);
28. // Convert "special" chars -- cause we never now... ;-)
29. $url = htmlspecialchars($url);
30. // "fallback" link, if the browser is not supporting header redirects
31. print '<a href="https://www.phpfensi.com' . $url.'">Please click here</a>';
32. // stop the script execution here
33. exit;
34. }
35. // If the domain is www.phpfensi.com then go on with your PHP code
36. // of with your website...
37. // BTW: You need to replace phpfensi.com trough your own domain :-D